This is the TeX Directory Structure (TDS) document, describing a runtime layout of TeX-related files intended to be portable, implementation-independent, etc. Most TeX distributions have adopted this in some form. If any questions, comments, or suggestions, email twg-tds@tug.org. Mailing list archives available at: http://tug.org/mail-archives/twg-tds/ tds.tex is the master source file. A few extra LaTeX packages that it uses are in packages.zip, in the unlikely event that you don't already have them. http://tug.org/tds/ contains the current released version. For older versions, see ftp://tug.org/historic/docs/tds. For the current development sources, see http://tds.sarovar.org. Happy installing.